I'm concerned about the recent behavior of the little Delta male I bought last June. Within the last few days he's taken to 'shivering' (the only way I can describe it) while floating both upright and, occasionally, on his side.

He zooms from place to place instead of swimming calmly as he used to. Then he hides or sits motionless on the bottom or on plant. And he is unnaturally skittish and nervous, a trait he has never shown in the past.

Sometimes he breaths heavily, mostly normaL. He still eats, but reluctantly.

He has always had a small white imperfection above his right eye. It seems to have grown larger.

He's alone in a bare-bottom 2.5gal unfiltered at 80* with lots of plants and a hide. Water gets changed 50%/90%every two or three days with Prime. He'll only eat frozen bloodworms. Water checks out 0,0,0 and 7.8Ph.

He's never been sick before. Although, he's never regrown the finnage he bit off several months ago.
I haven't attempted any treatment because I can't seem to find a description in the stickies that applies.

The plants are a couple of floating Aponogeton, a sunk Tiger Lily, some tied-down Anacharis and a small Anubias. The Anubias is still growing slowly; the Anacharis is stalled but green and the Aponogeton gets trimmed occasionally. He lives alone. This actually started before his last water change, but (and thanks for reminding me)....

Until three weeks ago, the tank had been moderately slimed with BGA (blue-green-algae) for months. I wiped it off every water change and he did fine. On a recommendation, I treatd the tank with unadulterated Rooibos tea. This became more diluted from water changes until it was clear. I haven't had any BGA for more than a week now. A few days ago, he started acting funny. I'm not sure I can make a connection.

His poop looks normal, just smaller and less frequent as he is eating less.

Im pretty new to all this myself, trying to learn more and be helpful with what i've learn. the white thing above his eye doesnt sound too good, especially if it has grown. May be if you take a photo of it, one of the more experienced betta keepers can tell you whether its a tumor or something more dangerous. Maybe you can send a message straight to Oldfishlady, your situation seems quite dire...

I would recommend putting him in a completely ornamentless qt with clean water heating and the rooibos. The roobis is pretty much like IALs, helps speed healing. The only thing i can think of is internal parasites, or one of those mysterious illnesses with a million symptoms like fish tb...there is no possibility of the water being contaminated correct?

don't be too hard on yourself, these are small creatures that cant communicate verbally with is. We can only do what we can. May I ask why he is on epsom salt? If he's not bloated I think you can use aquarium salt.

He's not shivering anymore; I don't think he has the energy. He's sitting (uptight) on the bottom or in/on his Anubias. Sometimes he'll tuck his head down into his plant for 15 or more minutes. I lowered the water level so he can sleep on his plant and easily get air. He still breathes heavily sometimes.

Unlike his normal behavior, he's still afraid of my hand and siphon (hand was food; siphon was curiosity). Zooms away at great speed, mostly in control, sometimes bumps tank wall. No white spots, no gold dust look. No marks or blemishes that I can see. No rubbing. Scales look normal, fins not clamped. His fins are drastically losing color but not his body.

Clean 81* water with Stress Coat and Rioobos; no salts.

I still can't identify anything by reading the sticky and other research.

Maybe youshould go for some broad spectrum medicine, I understand how frustrating it all is, but dont take it out on yourself when you've tried your best.
We can only do so much for these fish, give them better lives, do all we can to cure them. It's enough. But when a pet dies, all you can do is take the happy memories it has given you....